Summary: Camera Calibration Using Two Concentric
Circles
Francisco Abad , Emilio Camahort, and Roberto Viv´o
Universidad Polit´ecnica de Valencia, Camino de Vera s/n, Valencia 46021, Spain
{fjabad, camahort, rvivo}@dsic.upv.es,
WWW home page: http://www.sig.upv.es
Abstract. We present a simple calibration method for computing the
extrinsic parameters (pose) and intrinsic parameters (focal length and
principal point) of a camera by imaging a pattern of known geometry.
Usually, the patterns used in calibration algorithms are complex to build
(three orthogonal planes) or need a lot of features (checkerboard-like pat-
tern). We propose using just two concentric circles that, when projected
onto the image, become two ellipses. With a simple mark close to the
outer circle, our algorithm can recover the full pose of the camera.
Under the perfect pinhole camera assumption, the pose and the focal
length can be recovered from just one image. If the principal point of
the camera has to be computed as well, two images are required. We
present several results, using both synthetic and real images, that show
the robustness of our method.
1 Introduction